This paper briefly reviewed the Heisenberg model and its improvement by including higher order corrections, and their applications to bond lengths, stability, and reactivity of non-benzenoids and the low-lying excitation spectra of conjugated systems. Two efficient computational methods, the Lanczos method and the density-matrix renormalization group (DMRG), for exactly and approximately solving various Heisenberg models, respectively, were briefly introduced.
Density-Matrix Renormalization Group Study of Kitaev–Heisenberg Model on a Triangular Lattice
